Abstract

A major goal of the experimental program at the spectrometer ANKE, which is located at an internal target position of the COoler SYnchrotron COSY-Juelich, is the investigation of the light scalar resonances a0(980)/f0(980) close to the KKbar production threshold. It is foreseen to measure the a0/f0 production in hadron-induced reactions with different isospin configurations in the entrance channel, i.e. in pp, pn, pd and dd reactions. The first two experiments were carried out in the beginning of 2001 and 2002 for the pp channel at beam energies of T(p)=2.65 GeV (Q=46 MeV above the KKbar threshold) and 2.83 GeV (Q=103 MeV). Both measurements aimed at the detection of coincident dK+ and dpi+ pairs in order to investigate the a0+(980) resonance in the reaction chains pp -> d a0+ -> dK+Kbar0 / dpi+eta with a missing-mass analysis.\\ In the framework of this thesis both measurements were prepared with the help of Monte-Carlo simulations and the beam times of two and three weeks were organized and conducted. After the measurements the data were analyzed, focusing on the dK+ events obtained at T(p)=2.65 GeV.\\ With the help of the ANKE range telescopes, which are optimized for the identification of K+ mesons in a huge background of other particles, the kaons can be selected via their time-of-flight and energy losses. Coincident deuterons are identified via their time relative to the K+ mesons. A subsequent missing-mass analysis of the dK+ pairs reveals a clear peak at the mass of the Kbar0 meson with about 1000 events. For these dK+Kbar0 events the total production cross section of sigma(tot)=(38 +/- 2(stat) +/- 14(sys)) nb as well as differential mass and angular distributions have been determined. The total cross section, which is based on an effective measuring time of about 5 days, shows that systematic studies of the scalar resonances a0(980)/f0(980) are possible with ANKE. The mass and angular distributions indicate that a significant fraction of the K+Kbar0 pairs are produced via the a0+(980) resonance. They also suggest that the final- state interaction between the deuteron and the Kbar0 has to be taken into account for the interpretation of the data.